[PatrickHenry]

* Footnote in original article. Bold font added by me.

Everybody be nice.

[PatrickHenry]

PING. [This ping list is for the evolution side of evolution threads, and sometimes for other science topics. FReepmail me to be added or dropped.]

[woofer]

In the fish evolutionary tree, the coelacanth branch is pretty straight. Other branches have thousands of limbs, branches and twigs.

Like, say, some family trees in Arkansas that resemble telephone poles?

[WhiteGuy]

So...................

The answer was 42?


Seriously, who pays these people?

[Ichneumon]

A typical example of the living-fossil phenomenon is the coelacanth, a species of fish first identified by scientists after being caught in deep water off the coast of Africa in 1938. Scientists had believed it had gone extinct 80 million years earlier, but the discovery showed the unusual fish instead had survived unchanged for over 340 million years.

A common misperception, but still wrong. The coelacanth has *not* survived "unchanged". Modern coelacanths are significantly changed from the 340-million-year-old ancestral version, to the point where they are assigned not only to different species, but even to a different genus altogether.

They're still recognizably in the same family, though, which is considerably less evolutionary change than, say, a modern pelican compared to its ancestral therapsid dinosaur over the same timespan, but the point remains that the coelacanth is not actually "unchanged", and its evolution did not somehow "stop" during the last 300+ million years.

And varying amounts of evolutionary change in different lineages is no challenge to "darwinism", as some like to claim, since Darwin himself predicted this effect in his "Origin of Species" book back in 1859.

[Sabertooth]

"If one branch has more species, the chances are greater that it will speciate," Pinelis explains. "The rich get richer; money goes to money."

In real life, evolutionary trees are even more unbalanced than simple probability would predict. To explain this, Pinelis supposed that there must exist a significant number of species that change very slowly over time. His supposition is borne out in reality: Biologists have long puzzled over such species, which are sometimes called "living fossils.

Sounds like some common sense math. It's a double-edged sword, however, for another evolutionary notion currently in vogue, that of evolutionary clocks.

Just as we don't accrue wealth at constant rates, living fossils demonstrate that species don't accumulate mutations at constant rates, genera don't accumulate species at constant rates, etc. Evolutionary clocks are not analogous to radiometric clocks. The observed fact of relative evolutionary stasis vs. that of evolutionary dynamism calls conclusions based on evolutionary clocks into doubt

[Doctor Stochastic]

I read the Statistical Science article several years ago. I'll try to find the Proceedings of the Royal Society this week. (There is more than one Royal Society.)

[<1/1,000,000th%]

Not a very informative article.

Where's my Cheetos?

[patriot_wes]

"To a certain extent, the answer lies in simple probability, says Pinelis. Say you have two species of fish swimming in a pond, the carp and the perch, and it might be equally likely that one of them will evolve a third species. Say the goldfish evolves from the common carp, and suddenly you have three fish species in your pond."

SOLVED....the evolution of democRAT presidential cantidates

[colorado tanker]

Huh. And I thought the best example of the "living-fossil" phenomenon was Jimmy Carter.

[donh]

hmm. I wouldn't say the case is made here. Some genomes are going to have better meta-evolutionary strategies then others, and will prosper by prospecting for new niches to fill. More narrowly focused genomes will prosper best by honing themselves for being better at occupying the niche they are already in. Critters ain't necessarily markov chains at their fundament, just because a markov model seems to accurately reflect their behavior.